Millions of Californians have been warned their lights and air conditioning units could go out this week as the state plans rolling blackouts to deal with a record heatwave that has pushed the power grid to the limit.
With the first large-scale outages expected late on Monday, the situation brought an admission from governor Gavin Newsom that poor planning had left America’s most populous state ill-prepared for extremes in demand during the switch to renewable energy.
California has vastly expanded the capacity of solar power, and to a lesser extent wind power, in the past decade. The state also allowed a large nuclear power plant to shut down and has curtailed the growth of natural gas-fired generation.
The drawbacks of solar power have been evident in the past week as temperatures soared daily above 100 degrees Fahrenheit and air-conditioner use lept in the late afternoon and early evening — just as the sun set. Neighbouring states, usually a reliable source of electricity imports, had little left to sell as they slogged through the same heatwave, said officials at the California Independent System Operator (ISO), which manages the state’s grid.
“The load forecasts reflect the realities of climate change. It’s getting hotter,” Steve Berberich, California ISO’s chief executive, told its board at a meeting on Monday. “Unfortunately, it is near certain that we’ll be forced to ask the utilities to cut off power to millions today [Monday] to balance supply and demand — today and tomorrow, and perhaps beyond.”
Mr Berberich said his agency had warned the California Public Utility Commission for years of inadequate power during times of maximum demand. “The situation we are in could have been avoided,” he said.
California’s power sector has a fraught history. Widespread blackouts that followed a botched deregulatory effort two decades ago cost the state billions of dollars and led to the ousting of governor Gray Davis.
Wildfires sparked by equipment owned by Pacific Gas and Electric, which serves most of northern California, prompted the utility to temporarily suspend service to millions of customers last autumn to avoid causing new fires.
Another wildfire season is ablaze, with more than 20 active incidents reported by the California Department of Forestry and Fire Protection. But PG&E’s outages at the weekend, which affected 220,000 customers, came at the behest of the grid operator as it tried to cope with demand, the company said.
PG&E, Southern California Edison and San Diego Gas & Electric all warned customers of rotating outages while ISO urged consumers to voluntarily raise thermostats, close window blinds and keep refrigerator doors closed, among other conservation measures.
Shortfall versus California power demand expected on Monday evening
Mr Newsom sought answers from the grid operator, the utility commission and the state energy planning agency, but he said that California would stick to its clean-energy goals.
“None of us in California are immune or naive about the hots getting hotter, dries getting drier, wets getting wetter. We have long recognised the consequences of climate change,” Mr Newsom said. “We are committed to radically changing the way we produce and consume energy.”
As utilities searched for power supplies, wholesale power prices for delivery during the Monday peak surged to $400 a megawatt-hour, up from an average of about $30, said Morris Greenberg, senior manager of North America power analytics at S&P Global Platts.
Temperatures above 100 degrees Fahrenheit (38 degrees Celsius) that have baked western cities over the past several days are likely to continue. “We expect to see highs at least around the century mark on Thursday,” said Sierra Littlefield, a forecaster with the National Weather Service in Sacramento, California’s state capital.
Peak power demand was likely to reach 50,485MW on Tuesday, eclipsing a previous high set in the summer of 2006, ISO said. However, the state had more generating capacity in 2006 than in 2020, officials said, including the San Onofre nuclear power plant that has since closed.
On Monday evening, the state faced a shortfall of as much as 4,400MW, ISO said.
Mark Rothleder, California ISO’s vice-president of market policy and performance, said that the hot weather was making generation less efficient by adding cloud cover that diminished solar output and causing winds to flag. He said that natural gas-fired power plants also produced less in high temperatures than lower temperatures.
The ISO in June described a “low probability of a system capacity shortfall” but also warned that hydroelectric resources would be below normal because stocks of mountain snowmelt peaked at just 63 per cent of average levels this spring.
Michael Goggin, vice-president at Grid Strategies, a clean energy consultancy, said that the rapid adoption of batteries would help store up solar energy for discharge during peak periods. Battery capacity inside of California ISO would expand above 900MW by the end of the year from about 200MW today, he said.
“It’s an awkward time in the transition of the California grid,” Mr Goggin said.
However, Mr Berberich told the ISO board on Monday that “batteries won’t fix this alone. They will help, and they’re an important part of a renewable-heavy system. However, they don’t generate any power, and during extended periods of cloud cover over the solar field, there won’t be any energy to charge them.”